Resistance device



Feb. 17. 1925.

A.. E. WALLER RESISTANCE DEVICE Filed March 28. 1922 40 l ZINZZIVTOR BY W A A ATTORNEYS Patented Feb. 17,1925.

UNITED STATES 1,526,649 PATENT OFFICE.

ARD ELECTRIC COMPANY, A

I ALFRED ERNEST WALLER, OF BRONXVILLE, NEW YORK, ASSIGNOR TO WARD LEON- CORPORATION OF NEW YORK.

RESISTANCE DEVICE.

Application filed March 28, 1922. Serial No. 547,565.

To all whom it may concern:

Be it known that ALFRED E. \VALLER, a citizen of the United States, residing at Bronxville, in the county of lVestchester and State of New York, has invented certain new and useful Improvements in Resistance Devices, of which the following is a specification.

This invention relates to electrical resistance devices, or rheostats, particularly of the type wherein the resistor elements are of thin self-supporting strips, such as ribbon bent in the form of a channel, or ribbed longitudinally to give stiffness to the strip.

The present invention is especially desirable where the current passed through the resistor elements is comparatively large and where it is desirable to use resistor strips or ribbons of considerable width. The main object is to provide a simple form of construction in which the parts may be economically manufactured and conveniently and easily assembled and at the same time secure a desirable form of support at the ends of the-resistors and also secure a good electrical connection between the ends of the resistors and the contact segments of the rheostats or regulators. Another important object is to avoid the use of auxiliary cables or auxiliary connecting devices between the ends ofthe resistors and the contact segments. Heretofore where the resistor elements are of large size and occupy considerable space on the panel or base board, it has been customary to use auxiliary heavy cables, or copper wire conductors, in order to connect the ends of the resistor elements with the contact segments; and if it were attempted to mount these large sized resistor elements so that they would be directly connected with the contact segments, the size of theparts would have to be large, in order to secure suflicient electrical contact; and in heat dissipation, the contact segments would have such large distances from the center of one contact to the center of the next and the contact segments would be so large and the travel of the movable contact member would be so great, that the complete apparatus would be. comparatively large and likewise considerably increase the cost of manufacture. When it is desired to avoid this undesirable construction, and the wide resistor elements are mounted at a distance from the contact segments on the panel or base support and intervening connecting wires or cables are used, the size of the apparatus is even then unnecessarily large and the labor cost in assembling and connecting and the cost of the wire or cables is considerable.

By means of my invention I not only secure economy in cost of the material and labor but also secure a compact form of construction with direct connection between the resistor elements and the contact segments and at the same time secure ample spacing of the resistor elements to provide for heat dissipation. Other objects and advantages of my invention will be understood from the following description and acco1npanying drawings which illustrate a preferred embodiment thereof.

Fig. 1 is a rear elevation of a portion of a panel with resistor elements and connectors mounted thereon; Fig. 2 is an enlarged plan view on the line 22 of Fig. 1 showing one of the upper resistor elements and connecting parts; Fig. 3 is an enlarged side view on the line 33 of Fig. 1; Fig. t is an enlarged elevation showing the connecting and clamping means at one end of the resistor element; and Fig. 5 is a perspective View of one of the resistor elements before being bent for mounting in place.

The resistor element is formed from thin strips or ribbons of suitable resistant metal of the desired cross section and may be of considerable width. The ribbon is cut into #suitable lengths and bent into a channel forming the main portions 10 of the resistor element separated by a flat intervening portion 11 The end portions 12 are also fiat and have a perforation 13.-

The panel board or base 14, of insulatin material, carries a series of parallel meta strips 15 for supporting the resistor elements and for connecting them in series with each other and with the contact segments. These connectors or conductors 15 are of no greater width than the contact segments and may be as long as desired, for suitably connecting the resistor elements and for obtaining a suflicient spacing of the resistor elements from each other. The strips 15 may be made of copper, brass or iron and as they are comparatwely thin and rectangular in form maybe rapidly and Eli therein which coincide with the holes in the end portions of the resistor elements and through which passes the bolts 15. A rectangular washer 17 which is the width of the strips 15 and as long as the ribbon is wide, is placed over the end portions 13 and these end portions are thus clamped over their entire surface between the strips 15 and the washers Nuts 18 on the bolts 16 and on opposite sides of the washers 17 and strips serve to firmly and securely clamp the end portions of the resistor elements between the strips and washers and thus secure a good and ample electrical con nection of the end portions of therewith. The washers 17 and strips 15 not only cover the entire end portions 13 of the resistor elements but also extend to the line of the bend between the end portions and the main portions 10 of the resistor elements, thus securing not only an ample surface contact and good electrical connection, but also giving a firm and rigid support of the resistor elements.

At the inner ends of the strips 15 the bolts 16 extend through the panel board and engage the contact segments 19 on the face thereof, a washer 20 and a split spring washor 21 being preferably interposed between the panel board 14 and the inner nut 18.

The resistor elements are preferably bent in this instance, so that the edges of, the channel formed sectionsextend outwardly so as to economize in space occupied and the endportions 13 extend inwardly and toward each other.

Referring to Fig. 1 it will be noted that the left hand resistor element 1 is connected between the inner end of a strip 15 and the innerend of the adjacent strip 15 to the right. The end portions of this resistor element are connected directly by the construction already described, to adjacent contact segments 19. The next resistor element 1" is ofi'set from the resistor element 1 and is connected between the connecting strip 15 to which one end of resistor 1 is connected and the middle of the next connecting strip 15 at the right. There is'however no contact segments at the back of the ends of the resistor element 1 and it is only necessary to merely clamp its end portions between the strips 15 and washers 17 by the nuts 18 on the bolts 16 is already described; but if desued; the bolts 16 may pass through the panel 14 as shown in Fig. 2 for, more securely to each other and the resistors almanac holding the strips 15 in place. The next resistor element 1 is ofiset from the resistor element 1 and is connected between the upper end of the connecting strip 15 to which one end of the resistor 1 is connected and the next adjacent strip 15 at the right. The resistor element 1 is connected to the lower end of this strip and to the lower end of the next strip 15 at the right; and the ends of the element 1 areconnected respectively to contact segments as already described. The next resistor element 1 is ofiiset fzomthe element 1 and connected between adjacent strips as already described and so on.

will thus is that resistor elenents are moun in staggered relationship other so as to 'ive ample provision for dis sipation of th lea generated. Theinner ends of the stri 1 will be connected to a row of contactsegi-. ents 1 so that when the movable contact element passes over the segments, it will successively make an electrical connection with the inner ends of the strips 15. In the present case a similar set of resistor elements and connecting strips is shown in Fig. 1 oppositely located to the upper set and are connected to a row of con.- tact segments 19 soythat the movable con tact element 22 will successively bridge and connect oppositely located contact segments and include or'exclude resistor elements in the circuit accordingly. In some cases only one set of resistor elements may be used with one row of contact segments and these may be arranged on a straight line or on the arc of a circle as desired and engaged also spaced from each by a contact arm or by a movable contact element which is adapted to connect the contact segments successively with a continuous conducting strip. In some cases the contact segments may be located on the same side of the panel board as the resistor elements.

It will be seen that in the present instance where the resistor elements are arranged in sets of three in staggered relationship, the strips 15 can be made of two difierent lengths and only two different lengths are required. Of course instead of having the resistor elements arranged in sets of three, they could be arranged in sets offour; five or any desired number and. variously related. it being necemary only to make the length of the strips 15 correspond thereto.-

t ing strips connected thereto, and a series of resistor elements supported upon and electrically connected between ad oining strips respectively, the support and connection of the resistor elements to anyone strip being at displaced positions along said stripi 2. A resistance device comprising a row of contact segments, a series of fiat conducting strips connected thereto, and a series of resistor elements supported upon and electrically connected between adjoining strips respectively, the support and connection of the resistor elements to any one strip' being at displaced positions along said strip and spaced apart from each other.

3. A resistance device comprising a row of contact segments, a series of flat conductstrips connected thereto, and a series 0 resistor elements supported upon and electrically connected between adjoining strips respectively, the support and connection of the resistor elements to any one strip being at displaced positions along said strip and said resistor elements each having a flat end portion engaging the flat surface of said strips, a washer approximately equal to the width of said strip and width of said end portion and engaging said end portion, and means for clamping said end portion between a strip and one of said washers.

' 4; A resistance device comprising a row of contact segments, a series of flat conducting'strips connected thereto, a series of thin reslstor elements connected to said strips,

said resistor elements having flat end portions bent at an angle to the main portions thereof, said end portions engaging the face of said strips at displaced positions thereon, and means for clamping said end portions to said strips.

5. A resistance device comprising a row of contact segments, a series of flat conducting strips connected thereto, and a series of resistor elements supported upon and elec- .trically connected between adjoining strips respectively, the support and connection of the resistor elements to any one strip being at displaced positions along said strip, the said resistor elements being in staggered relationship to each other.

6. A resistance device comprising a base, a series of conducting strips mounted thereon, a series of ribbon resistor elements having channeled main portions, said main portions being bent at an angle to each other, each of said resistor elements having flat end portions bent at an angle tothe main portions, said flat portions engaging said strips respectively at positions displaced from each other along said strips and said resistor elements extending from said base in planes perpendicular to said base.-

7. A resistance device comprising a row of contact segments, a series of flat conducting strips connected thereto, and a series of resistor elements supported upon and electrically connected between adjoining strips respectively, the support and connection of the resistor elements to any one strip being at displaced positionsalong said strip, and said strips having different lengths and each of said strips having one of said resistor elements supported upon and electrically connected to its outer end.

ALFRED ERNEST WALLER. 

